Deaeration device for thermal system

ABSTRACT

A deaeration device for a fluid includes a reservoir that contains a portion of the fluid, a fluid flow path that carries a portion of the fluid, a pressure regulating structure that creates a pressure gradient along the fluid flow path, a fluid exit in the fluid flow path, and a fluid entrance in the fluid flow path. The pressure gradient causes some of the fluid to exit the fluid flow path through the fluid exit and join the fluid in the reservoir. The pressure gradient causes some of the fluid from the reservoir to join the fluid flow path through the fluid entrance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/571,909, filed on Oct. 13, 2017, and U.S. Provisional Application No.62/647,979, filed on Mar. 26, 2018, and is a continuation of UnitedStated Patent application Ser. No. 16/120,569, filed on Sep. 4, 2018,the contents of which are hereby incorporated by reference in theirentirety for all purposes.

TECHNICAL FIELD

The application relates generally to thermal heating and/or coolingsystems that utilize a liquid media.

BACKGROUND

Liquid heating and/or cooling systems circulate a liquid media through asystem. The liquid media travels between components before returning toits starting point, in what is commonly referred to as a thermal loop, acooling loop, or a heating loop. Air can be introduced into the liquidmedia, for example, during filling, when the liquid media is added tothe system. Air bubbles in the liquid media can cause corrosion to someportions of the system and can cause damage to some portions of thesystem. The presence of air in the liquid media can also reduce thethermal performance, flow rate, and heat capacity of the system.

SUMMARY

One aspect of the disclosed embodiments is a deaeration device for afluid. The deaeration device includes a reservoir that contains aportion of the fluid, a fluid flow path that carries a portion of thefluid, a pressure regulating structure that creates a pressure gradientalong the fluid flow path, a fluid exit in the fluid flow path, and afluid entrance in the fluid flow path. The pressure gradient causes someof the fluid to exit the fluid flow path through the fluid exit and jointhe fluid in the reservoir. The pressure gradient causes some of thefluid from the reservoir to join the fluid flow path through the fluidentrance.

In some implementations, the fluid exit is located at a first end of thepressure regulating structure in a high-pressure region and the fluidentrance is located at a second end of the pressure regulating structurein a low-pressure region.

In some implementations, a first portion of the fluid flow path islocated before the pressure regulating structure in a fluid-flowdirection, a second portion of the fluid flow path is located after thepressure regulating structure in the fluid-flow direction, and a firstelevation of the first portion of the fluid flow path is higher than asecond elevation of a second portion of the fluid flow path.

In some implementations, the pressure regulating structure includes areverse curvature defined along the fluid flow path. The reversecurvature may include a first curve and a second curve, wherein thefluid exit is located along the first curve, and the fluid entrance islocated along the second curve. Alternatively, the reverse curvature mayinclude a first curve and a second curve, wherein the fluid exit islocated before the first curve in a fluid flow direction, and the fluidentrance is after the second curve in a fluid flow direction.

In some implementations, the fluid exit includes a single opening andthe fluid entrance includes a single opening. In some implementations,the fluid exit includes multiple openings and the fluid entranceincludes multiple openings.

In some implementations, the fluid flow path is defined by a conduit.The conduit may extend through the reservoir.

Another aspect of the disclosed embodiments is a deaeration device for afluid. The deaeration device includes a reservoir that contains aportion of the fluid and a fluid flow path that carries a portion of thefluid. A baffle structure that is disposed in the reservoir and definesa first chamber, a second chamber, and one or more intermediate chambersin the reservoir. A curvature is defined along the fluid flow path. Thecurvature serves as a pressure regulating structure that creates apressure gradient along the fluid flow path. A fluid exit is defined inthe fluid flow path and is in communication with the first chamber. Thepressure gradient causes some of the fluid to exit the fluid flow paththrough the fluid exit and join the fluid in the reservoir. A fluidentrance is in the fluid flow path and is in communication with thesecond chamber. The pressure gradient causes some of the fluid from thereservoir to join the fluid flow path through the fluid entrance. Thebaffle structure causes fluid from the first chamber to travel throughthe one or more intermediate chambers before reaching the secondchamber.

In some implementations, the fluid flow path passes through the bafflestructure. In some implementations, the curvature includes a curve thatextends through an arc that is greater than ninety degrees. In someimplementations, the curvature includes a curve that extends through anarc that is at least one-hundred and eighty degrees. In someimplementations, the fluid exit is located along the curve and the fluidexit is located after the curve. In some implementations, the fluid flowpath is defined by a conduit. In some implementations, the conduitextends through the reservoir.

Another aspect of the disclosed embodiments is a thermal system thatcirculates a fluid. The thermal system includes a pump, a functionalcomponent that generates heat, a cooling device, and a deaerationdevice. The deaeration device includes a reservoir that contains aportion of the fluid, a fluid flow path that carries a portion of thefluid, and a curvature that is formed in the fluid flow path to create apressure gradient along the fluid flow path. A fluid exit is defined inthe fluid flow path, wherein the pressure gradient causes some of thefluid to exit the fluid flow path through the fluid exit and join thefluid in the reservoir. A fluid entrance is defined in the fluid flowpath, wherein the pressure gradient causes some of the fluid from thereservoir to join the fluid flow path through the fluid entrance. Thethermal system also includes conduits that interconnect the pump, thefunctional component, the cooling device, and the deaeration device.

The deaeration device may also include a baffle structure that isdisposed in the reservoir and defines a first chamber, a second chamber,and one or more intermediate chambers in the reservoir, wherein thefluid exit is in communication with the first chamber of the bafflestructure, the fluid entrance is in communication with the secondchamber of the baffle structure, the baffle structure causes fluid fromthe first chamber to travel through the one or more intermediatechambers before reaching the second chamber, and the fluid flow pathpasses through the baffle structure.

In some implementations, the curvature that is formed in the fluid flowpath includes a curve that extends through an arc that is at leastone-hundred and eighty degrees, the fluid exit is located along thecurve, and the fluid exit is located after the curve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration that shows a thermal system.

FIG. 2 is a schematic illustration that shows a deaeration device of thethermal system according to a first example.

FIG. 3 is a cross-section illustration that shows a deaeration device ofthe thermal system according to a second example.

FIG. 4 is a cross-section illustration that shows a deaeration device ofthe thermal system according to a third example.

FIG. 5 is a cross-section illustration that shows a deaeration device ofthe thermal system according to a fourth example.

FIG. 6 is a side view illustration that shows a deaeration deviceaccording to a fifth example.

FIG. 7 is a perspective view that shows a reservoir of the deaerationdevice of FIG. 6 .

FIG. 8 is a cross-section view of the reservoir of the deaeration deviceof FIG. 6 , taken along line 8-8 of FIG. 6 .

FIG. 9 is a cross-section view of the reservoir of the deaeration deviceof FIG. 6 , taken along line 9-9 of FIG. 8 .

FIG. 10 is a cross-section view of the reservoir of the deaerationdevice of FIG. 6 , taken along line 10-10 of FIG. 8 .

DETAILED DESCRIPTION

Traditional high flow liquid cooling systems use a constant bleed. Thismeans that some of the fluid flow that would otherwise be used to coolfunctional devices is constantly being lost back to the reservoir, whichreduces efficiency. This efficiency loss has been considered acceptablein internal combustion engine designs, which by design operate at hightemperatures and with relatively low efficiency.

Traditional low flow liquid cooling systems pass all of their fluid flowdirectly through a reservoir. While this approach is acceptable at lowflow rates, at higher flow rates the liquid in the reservoir will becometurbulent and aeration results.

Electric vehicles operate at higher efficiency levels as compared tointernal combustion engine vehicles, and at much lower temperatures. Theefficiency penalty of a constant-bleed deaeration system would have adetrimental impact on the overall effectiveness of the cooling system inan electric vehicle application.

The disclosure herein is directed to a thermal system that includes adeaeration device that operates at high flow rates with much higherefficiency as compared to constant bleed systems. As an example, thedeaeration device may include a fluid flow path that extends through areservoir and defines a reverse curve (i.e., an S-curve). The reversecurve creates a pressure differential between a first opening and asecond opening. The first opening expels air and liquid into thereservoir. The second opening entrains liquid into the fluid flow path.A portion (e.g., a majority) of the liquid carried by the fluid flowpath remains in the fluid flow path without entering the reservoir.

FIG. 1 is an illustration that shows a thermal system 100. The thermalsystem 100 includes a deaeration device 102, a pump 103, a functionalcomponent 104, and a cooling device 106. The various components of thethermal system 100 are interconnected by conduits 108 that circulate afluid media 110 between the components.

In the illustrated example, the thermal system 100 is a cooling system,which provides an example of a system in which the deaeration device 102can be implemented. The deaeration device 102 can also be implemented ina heating system, or a combined heating and cooling system. The pump 103is connected to the deaeration device 102 by one of the conduits tocause the fluid media 110 to flow from the deaeration device 102 to thefunctional component 104.

The functional component 104 is a device or system that is to bemaintained at a controlled temperature. Thus, a desired temperature canbe determined for the functional component 104, and the thermal system100 is operated to maintain the functional component 104 within anacceptable temperature range relative to the desired temperature bydelivery of the fluid media 110 to the functional component 104. Thefunctional component 104 may be one of several devices or systems thatare thermally regulated by the thermal system 100. The functionalcomponent 104 may be a heat-generating component. As an example, thethermal system 100 can be utilized in an electric vehicle application inwhich the functional components include batteries, electric motors, andcomputing devices that control various systems of the vehicle. The fluidmedia 110 exits the functional component 104 through one of the conduits108 and is directed to the cooling device 106.

The cooling device 106 may be any device that can reduce the temperatureof the fluid media 110. As examples, the cooling device 106 can be aheat exchanger, a heat pump, or a thermoelectric cooler. Inimplementations in which the thermal system 100 is a heating system, thecooling device 106 may be omitted in favor of a heating device, such asan electric heater. In implementations in which the thermal system 100is a combined heating and cooling system, a heating device may beincluded in addition to the cooling device 106.

The conduits 108 are structures that are able to transport liquids, suchas the fluid media 110. As an example, the conduits 108 may be hoses.The fluid media 110 can be, for example, an ethylene glycol-based liquidcoolant, and may include air bubbles.

FIG. 2 is a schematic illustration that shows the deaeration device 102of the thermal system 100. The deaeration device 102 includes areservoir 212, a first fluid portion 215 a of the fluid media 110 thatis held in the reservoir, a fluid flow path defined through a conduit214, a second fluid portion 215 b that is carried by the conduit 214, apressure regulating structure 216 that is defined along the fluid flowpath, a fluid exit 218, and a fluid entrance 220

The reservoir 212 holds the first fluid portion 215 a. While the firstfluid portion 215 a is located in the reservoir 212, air that is mixedinto the first fluid portion 215 a may settle out of the first fluidportion 215 a, such as by rising above a fluid level within thereservoir 212 and joining a volume of air (and/or other gases) that arecontained in the reservoir 212 above the fluid level.

The conduit 214 is an example structure that can carry the second fluidportion 215 b through or past the reservoir 212 with limited fluidcommunication between the first fluid portion 215 a that is located inthe reservoir 212 and the second fluid portion 215 b that is carried bythe conduit 214. The second fluid portion 215 b moves through theconduit 214 in a flow direction, as indicated by arrows in FIG. 2 . Amajority of the second fluid portion 215 b continues through the conduit214 along the fluid flow path without mixing with the first fluidportion 215 a in the reservoir 212.

The pressure regulating structure 216 creates a pressure gradient alongthe fluid flow path. As used herein, the term “pressure gradient” refersto an area over which the pressure of a fluid changes, for example, bychanging from a low pressure at a first point to a high pressure at asecond point that is spaced from the first point by a distance. Forexample, the pressure regulating structure 216 may cause a high-pressurearea near the fluid exit 218, and a low-pressure area near the fluidentrance 220. The pressure regulating structure 216 may be anystructural configuration of the conduit 214 or any structure that isplaced in or defined on the conduit 214 that is operable to change thepressure of the second fluid portion 215 b as it flows through theconduit. As examples, the pressure regulating structure may include acurvature (e.g., one or more bends), a restriction, or a baffle.

The fluid exit 218 is located at a first end of the pressure regulatingstructure 216 in a high-pressure region and the fluid entrance 220 islocated at a second end of the pressure regulating structure in alow-pressure region. The fluid exit 218 is a fluid expelling structurethat allows a portion of the fluid carried by the fluid flow path toexit the fluid flow path in the conduit 214 and enter the reservoir 212.As an example, the fluid exit 218 may include a single opening that isformed through a wall of the conduit 214, multiple openings that areformed through the wall of the conduit 214, or a discontinuity in theconduit 214. The fluid entrance 220 is a fluid entraining structure thatallows a portion of the fluid in the reservoir 212 to enter the conduit214 and join the fluid flow path. As an example, the fluid entrance 220may include a single opening that is formed through the wall of theconduit 214, multiple openings that are formed through the wall of theconduit 214, or a discontinuity in the conduit 214.

The pressure gradient causes movement of a portion of the fluid media110 from the second fluid portion 215 b to the first fluid portion 215a. In particular, the pressure gradient created by the pressureregulating structure 216 causes some of the fluid from the second fluidportion 215 b of the fluid media 110 to exit the fluid flow path in theconduit 214 through the fluid exit 218, as indicated by arrow 219, andjoin the first fluid portion 215 a of the fluid media 110 in thereservoir 212. The pressure gradient also causes movement of a portionof the fluid media 110 from the first fluid portion 215 a to the secondfluid portion 215 b. In particular, the pressure gradient created by thepressure regulating structure 216 causes some of the fluid from thefirst fluid portion 215 a of the fluid media 110 in the reservoir 212 toenter the fluid flow path in the conduit 214 through the fluid entrance220, as indicated by arrow 221, and join the second fluid portion 215 b.

Movement of the fluid between the second fluid portion 215 b and thefirst fluid portion 215 a reduces the amount of air that is present inthe second fluid portion 215 b that is present in the conduit 214 and iscirculated through the thermal system 100. The fluid exit 218 and thefluid entrance 220 are positioned such that the fluid that will leavethe conduit 214 through the fluid exit 218 has more air in it than thefluid that will enter the conduit 214 through the fluid entrance 220.For example, the configuration of the reservoir 212 can be such thatdeaerated fluid tends to collect at a certain location (e.g., at anelevation bottom of the reservoir 212), and the fluid entrance 220 ispositioned at such a location.

FIG. 3 is a cross-section illustration that shows a deaeration device302 according to a further example that can be incorporated in thethermal system 100 in place of the deaeration device 102. The deaerationdevice 302 includes a reservoir 312, a first fluid portion 315 a in thereservoir 312, a conduit 314, a second fluid portion 315 b that followsa fluid flow path in the conduit 314, a reverse curve 316 (i.e., anS-curve) defined by the conduit 314 to function as a pressure regulatingstructure, a fluid exit 318, and a fluid entrance 320. These componentsare as described with respect to similar components of the deaerationdevice 102, except as noted.

In the illustrated example, the conduit 314, the fluid exit 318, and thefluid entrance 320 all have circular cross-sections. The diameters ofthe fluid exit 318 and the fluid entrance 320 are half or less of thediameter of the inside diameter of the conduit 314. The fluid exit 318and the fluid entrance 320 can be the same size or can be differentsizes. Although the fluid exit 318 and the fluid entrance 320 aredepicted as single openings, each can be implemented as multipleopenings.

As a pressure regulating structure, the deaeration device 302 includesthe reverse curve 316, which is defined along the fluid flow path of theconduit 314. In the illustrated example, the reverse curve 316 includesa first curve 317 a and a second curve 317 b. In the illustratedexample, the fluid exit 318 is located along the first curve 317 a onthe radially outward side of the conduit 314 relative to the first curve317 a, and the fluid entrance 320 is located along the second curve 317b on the radially outward side of the conduit 314 relative to the secondcurve 317 b. The fluid exit 318 and the fluid entrance 320 can bepositioned differently. For example, the fluid exit 318 can be locatedbefore the first curve 317 a in a fluid flow direction, and the fluidentrance 320 can be located after the second curve 317 b in a fluid flowdirection.

The conduit 314 includes an elevation change relative to the reservoir312 at the reverse curve 316. A first portion of the fluid flow pathdefined by the conduit 314 is located before the reverse curve 316 in afluid-flow direction, a second portion of the fluid flow path defined bythe conduit 314 is located after the reverse curve 316 in the fluid-flowdirection, and a first elevation of the first portion of the fluid flowpath is higher than a second elevation of a second portion of the fluidflow path.

In the illustrated example, the reverse curve 316 functions as apressure regulating structure for the conduit 314 and includes twocurves in opposite directions. In alternative implementations,additional curves can be included in the conduit 314. For example, fourcurves can be formed in the conduit 314 to function as a pressureregulating structure.

FIG. 4 is a cross-section illustration that shows a deaeration device402 according to a further example that can be incorporated in thethermal system 100 in place of the deaeration device 102. The deaerationdevice 402 includes a reservoir 412, a first fluid portion 415 a in thereservoir 412, a conduit 414, a second fluid portion 415 b that followsa fluid flow path in the conduit 414, a compound curvature 416 definedby the conduit 414 to function as a pressure regulating structure, afluid exit 418, and a fluid entrance 420. These components are asdescribed with respect to similar components of the deaeration device302, except as noted.

As a pressure regulating structure, the deaeration device 402 includesthe compound curvature 416, which is defined along the fluid flow pathof the conduit 414. In the illustrated example, the compound curvature416 includes a first curve 417 a, a second curve 417 b, a third curve417 c, and a fourth curve 417 d. The first curve 417 a, the second curve417 b, the third curve 417 c, and the fourth curve 417 d are two pairsof reverse curves in a stair step configuration, turning downward, thenlevel, then downward, then level.

In the illustrated example, the fluid exit 418 is located along thefirst curve 417 a on the radially outward side (upward facing) of theconduit 414 relative to the first curve 417 a, and the fluid entrance420 is located along the fourth curve 417 d on the radially outward side(downward facing) of the conduit 414 relative to the fourth curve 417 d.The fluid exit 418 and the fluid entrance 420 can be positioneddifferently. For example, the fluid exit 418 can be located before thefirst curve 417 a in a fluid flow direction, and the fluid entrance 420can be located after the fourth curve 417 d in a fluid flow direction.

The conduit 414 includes an elevation change relative to the reservoir412 at the compound curvature 416. A first portion of the fluid flowpath defined by the conduit 414 is located before the compound curvature416 in a fluid-flow direction, a second portion of the fluid flow pathdefined by the conduit 414 is located after the compound curvature 416in the fluid-flow direction, and a first elevation of the first portionof the fluid flow path is higher than a second elevation of a secondportion of the fluid flow path.

FIG. 5 is a cross-section illustration that shows a deaeration device502 according to a further example that can be incorporated in thethermal system 100 in place of the deaeration device 102. The deaerationdevice 502 includes a reservoir 512, a first fluid portion 515 a in thereservoir 512, a conduit 514, a second fluid portion 515 b that followsa fluid flow path in the conduit 514, a compound curvature 516 definedby the conduit 514 to function as a pressure regulating structure, afluid exit 518, and a fluid entrance 520. These components are asdescribed with respect to similar components of the deaeration device302, except as noted.

As a pressure regulating structure, the deaeration device 502 includesthe compound curvature 516, which is defined along the fluid flow pathof the conduit 514. In the illustrated example, the compound curvature516 includes a first curve 517 a, a second curve 517 b, a third curve517 c, and a fourth curve 517 d. The first curve 517 a, the second curve517 b, the third curve 517 c, and the fourth curve 517 d are two pairsof reverse curves in a u-shaped configuration, turning downward, thenlevel, then upward, then level.

In the illustrated example, the fluid exit 518 is located along thefirst curve 517 a on the radially outward side (upward facing) of theconduit 514 relative to the first curve 517 a, and the fluid entrance520 is located along the fourth curve 517 d on the radially inward side(downward facing) of the conduit 514 relative to the fourth curve 517 d.The fluid exit 518 and the fluid entrance 520 can be positioneddifferently. For example, the fluid exit 518 can be located before thefirst curve 517 a in a fluid flow direction, and the fluid entrance 520can be located after the fourth curve 517 d in a fluid flow direction.

The conduit 514 includes an elevation change relative to the reservoir512 at the compound curvature 516. A first portion of the fluid flowpath defined by the conduit 514 is located before the compound curvature516 in a fluid-flow direction, a second portion of the fluid flow pathdefined by the conduit 514 is located after the compound curvature 516in the fluid-flow direction, and a first elevation of the first portionof the fluid flow path is higher than a second elevation of a secondportion of the fluid flow path.

FIG. 6 is a side view illustration that shows a deaeration device 602according to a further example that can be incorporated in the thermalsystem 100 in place of the deaeration device 102. The deaeration device602 includes a reservoir 612, a cover 613, a first fluid portion 615 ain the reservoir 612, a fluid inlet 622 that is connected to thereservoir 612 to receive a second fluid portion 615 b, and a fluidoutlet 624 that is connected to the reservoir 612. The cover 613 isconnected to the reservoir 612, for example, by fasteners or by snapfit, and may be removable. The cover 613 may include an opening that isfitted with a cap, for example, to allow fluid to be added to or removedfrom the reservoir 612. Other components may be connected to and/orextend through openings formed through the reservoir 612 and/or thecover 613.

FIG. 7 is a perspective view that shows the reservoir 612 of thedeaeration device 602. The reservoir 612 is configured to contain thefirst fluid portion 615 a (not shown in FIG. 7 ) within an internalspace 730 that is defined by a bottom wall 732, a peripheral wall 734that extends generally upward from the bottom wall 732, and a rim 736that is formed at the upper extent of the peripheral wall 734 and isconfigured for connection to the cover 613. In the illustrated example,the reservoir 612 is generally rectangular, with slight deviations froma true rectangular shape in the form of, as examples, discontinuities inthe elevation of the bottom wall 732, and angles and tapers applied tothe peripheral wall 734. It should be understood, however, that anysuitable geometric configuration can be utilized for the reservoir 612.As an example, the shape of the reservoir 612 may be dictated bypackaging constraints.

A baffle assembly 738 is located within the internal space 730 of thereservoir 612 in order to divide the internal space 730. The baffleassembly 738 also serves to control flow of the first fluid portion 615a within the internal space 730, as will be described in detail herein.Portions of the baffle assembly 738 or all of the baffle assembly 738may, in some implementations, be formed integrally with the reservoir612 of the deaeration device 602.

FIG. 8 is a cross-section view of the reservoir 612 of the deaerationdevice 602, taken along line 8-8 of FIG. 6 , showing the baffle assembly738 and a conduit 814. The baffle assembly 738 includes longitudinallyextending wall portions 840 a and the laterally extending wall portions840 b. The longitudinally extending wall portions 840 a and thelaterally extending wall portions 840 b divide the internal space 730 ofthe reservoir 612 into chambers that each contain part of the firstfluid portion 615 a and enforce a direction for flow of the first fluidportion 615 a within the internal space 730 of the reservoir 612. Thelongitudinally extending wall portions 840 a extend generally upwardrelative to the bottom wall 732 of the reservoir 612 and have agenerally planar configuration that also extends along a long axis ofthe reservoir 612 (i.e., in an end-to-end direction of the reservoir612). The laterally extending wall portions 840 b extend generallyupward relative to the bottom wall 732 of the reservoir 612 and have agenerally planar configuration that also extends along a short axis ofthe reservoir 612 (i.e., in a side-to-side direction of the reservoir612). The laterally extending wall portions 840 b intersect thelongitudinally extending wall portions 840 a, such that thelongitudinally extending wall portions 840 a and the laterally extendingwall portions 840 b cooperate to divide the internal space 730 of thereservoir 612.

In the illustrated example, the internal space 730 of the reservoir 612is divided into multiple chambers by the baffle assembly 738, includingan exit chamber 842 a (where fluid exits the conduit 814, as will bedescribed herein), an entrance chamber 842 b (where fluid enters theconduit 814, as will be described herein), and intermediate chambers 842c (i.e., one or more intermediate chambers) that define a fluid flowpath through the internal space 730 of the reservoir 612 between theexit chamber 842 a and the entrance chamber 842 b. Adjacent chambersfrom the exit chamber 842 a, the entrance chamber 842 b, and theintermediate chambers 842 c may be connected by fluid passages 844. Asexamples, the fluid passages 844 may be defined as gaps between thebaffle assembly 738 and the reservoir 612 (i.e., a gap relative to thebottom wall 732 and/or the peripheral wall 734), or as openings (e.g.,in the form of apertures of notches relative to a top edge of the baffleassembly 738). In the case of openings formed through the longitudinallyextending wall portions 840 a or the laterally extending wall portions840 b of the baffle assembly 738, a bottom edge of the opening may bespaced above the elevation of the bottom wall 732 of the reservoir 612.

FIG. 9 is a cross-section view of the reservoir of the deaeration deviceof FIG. 6 , taken along line 9-9 of FIG. 8 , and FIG. 10 is across-section view of the reservoir of the deaeration device of FIG. 6 ,taken along line 10-10 of FIG. 8 . As seen in FIGS. 8-10 , the conduit814 is located in the internal space 730 of the reservoir 612. Theconduit 814 is connected to the fluid inlet 622 and the fluid outlet 624and defines a fluid flow path that carries the first fluid portion 615a. As described in previous examples, most of the fluid that enters theconduit 814 as the first fluid portion 615 a is carried through thereservoir 612 within the conduit 814 without joining the second fluidportion 615 b within the internal space 730 of the reservoir 612, as thewalls of the conduit 814 separate the interior of the conduit 814 fromthe remainder of the internal space 730 of the reservoir.

In order to deaerate the first fluid portion 615 a, part of the firstfluid portion 615 a leaves the conduit 814 and joins the second fluidportion 615 b at a fluid exit 818, and part of the second fluid portion615 b, after deaeration within the internal space 730, leaves theinternal space 730 and joins the first fluid portion 615 a within theconduit 814 at a fluid entrance 820. The fluid exit 818 is located inthe exit chamber 842 a that is defined in the internal space 730 of thereservoir 612 by the baffle assembly 738. The fluid entrance 820 islocated in the entrance chamber 842 b that is defined in the internalspace 730 of the reservoir 612 by the baffle assembly 738. Thus, inorder for fluid within the second fluid portion 615 b to flow from thefluid exit 818 to re-enter the conduit 814 at the fluid entrance 820,the fluid travels through the exit chamber 842 a, through one or more ofthe intermediate chambers 842 c, and through the entrance chamber 842 b,where it may re-enter the conduit 814 at the fluid entrance 820.

A curvature 616 is defined by the conduit 814 to function as a pressureregulating structure, so that part of the first fluid portion 615 aleaves the conduit 814 at the fluid exit 818, and so that part of thesecond fluid portion 615 b enters the conduit 814 at the fluid entrance820.

In the illustrated example, the conduit 814, the fluid exit 818, and thefluid entrance 820 all have circular cross-sections. The diameters ofthe fluid exit 818 and the fluid entrance 820 are half or less of thediameter of the inside diameter of the conduit 814. The fluid exit 818and the fluid entrance 820 can be the same size or can be differentsizes. Although the fluid exit 818 and the fluid entrance 820 aredepicted as single openings, each can be implemented as multipleopenings.

As a pressure regulating structure, the deaeration device 602 includesthe curvature 816, which is defined along the fluid flow path of theconduit 814. In the illustrated example, the curvature 816 includes afirst curve 817 a and a second curve 817 b. The first curve 817 a is anapproximately ninety-degree bend in the conduit 814 that occurs justabove the bottom wall 732 of the reservoir 612 after the conduit 814passes through the bottom wall 732 on a path that is generallyperpendicular to the bottom wall 732. As used herein, the term“approximately” includes deviations expected as a result ofmanufacturing variations and measuring variations. Within the reservoir612, including along the second curve 817 b, the path of the conduit 814lies in a plane that is generally parallel to the bottom wall 732 of thereservoir 612. In some implementations, the second curve 817 b extendsalong an arc that is greater than or equal to ninety degrees. In someimplementations, the second curve 817 b extends along an arc that isgreater than or equal to one-hundred and eighty degrees. In theillustrated example, the second curve 817 b extends along an arc that isgreater than one-hundred and eighty degrees and is less than two-hundredand seventy degrees. Along the second curve 817 b, the conduit 814passes through one of the longitudinally extending wall portions 840 aof the baffle assembly 738.

In the illustrated example, the fluid exit 818 is positioned along thecurvature 816 between the first curve 817 a and the second curve 817 b,near the beginning of the second curve 817 b, and on the radiallyoutward side of the conduit 814 relative to the second curve 817 b, andthe fluid entrance 820 is located after the curvature 816, along astraight section of the conduit 814. The fluid exit 818 and the fluidentrance 820 can, however, be positioned differently relative to thecurvature 816. As a result of the pressure-regulating structure definedby the curvature 816, the fluid exit 818 is located at a first end ofthe curvature 816 in a high-pressure region and the fluid entrance 820is located at a second end of the curvature 816 in a low-pressureregion.

In the illustrated example, the fluid exit 818 and the fluid entrance820 of the conduit 814 are located at a common elevation. The fluid exit818 and the fluid entrance 820 could, however, be located at differentelevations. As previously described, the fluid exit 818 and the fluidentrance 820 can each include a single opening that is formed in theconduit 814 or multiple openings that are formed through the conduit814. The conduit 814 may be otherwise free from openings in the internalspace 730 of the reservoir.

What is claimed is:
 1. A deaeration device for a fluid, comprising: areservoir that contains a portion of the fluid; a conduit that carries aportion of the fluid through the reservoir, the conduit having a firstcurve and a second curve that are curved in opposite directions along afluid flow path; a fluid exit defined by the conduit, wherein the firstcurve and the second curve create a high-pressure region in the conduitat the fluid exit that causes some of the fluid to pass out of theconduit at the fluid exit and join the fluid in the reservoir; and afluid entrance defined by the conduit, wherein the first curve and thesecond curve create a low-pressure region in the conduit at the fluidentrance that causes some of the fluid from the reservoir to pass intothe conduit at the fluid entrance.
 2. The deaeration device of claim 1,wherein the fluid exit is located at a first end of the conduit in thehigh-pressure region and the fluid entrance is located at a second endof the conduit in the low-pressure region.
 3. The deaeration device ofclaim 1, wherein a first elevation of the first curve is higher than asecond elevation of the second curve.
 4. The deaeration device of claim1, wherein the fluid exit is located along the first curve, and thefluid entrance is located along the second curve.
 5. The deaerationdevice of claim 4, wherein the fluid exit is located on a first radiallyoutward side of the conduit and the fluid entrance is located on asecond radially outward side of the conduit.
 6. The deaeration device ofclaim 1, wherein the fluid exit is located before the first curve in afluid flow direction, and the fluid entrance is located after the secondcurve in the fluid flow direction.
 7. The deaeration device of claim 1,wherein the fluid entrance includes a single opening and the fluid exitincludes a single opening.
 8. The deaeration device of claim 1, whereinthe fluid entrance includes multiple openings and the fluid exitincludes multiple openings.
 9. The deaeration device of claim 1, whereinthe conduit, the fluid exit, and the fluid entrance have circularcross-sections.
 10. The deaeration device of claim 9, wherein the fluidexit and the fluid entrance each have a diameter that is more than fiftypercent smaller than an inner diameter of the conduit.
 11. A deaerationdevice for a fluid, comprising: a reservoir that contains a portion ofthe fluid; a fluid flow path that carries a portion of the fluid; apressure regulating structure having a first reverse curve and a secondreverse curve defined along the fluid flow path; wherein the firstreverse curve causes some of the fluid to pass through a fluid exit inthe fluid flow path and join the fluid in the reservoir; and wherein thesecond reverse curve causes some of the fluid from the reservoir to passthrough a fluid entrance in the fluid flow path and join the fluid inthe fluid flow path.
 12. The pressure regulating structure of claim 11,further comprising a conduit that defines the first reverse curve andthe second reverse curve, the first reverse curve including a firstcurve and a second curve, and the second reverse curve including a thirdcurve and a fourth curve.
 13. The pressure regulating structure of claim12, wherein the fluid exit is located along the first curve and thefluid entrance is located along the fourth curve.
 14. The pressureregulating structure of claim 13, wherein the fluid exit is located on afirst radially outward side of the conduit and the fluid entrance islocated on a second radially outward side of the conduit.
 15. Thedeaeration device of claim 14, wherein the conduit extends through thereservoir.
 16. The pressure regulating structure of claim 11, whereinthe first reverse curve and the second reverse curve have a stair stepconfiguration.
 17. The pressure regulating structure of claim 16,wherein the stair step configuration is directed downward along thefluid flow path.
 18. A deaeration device for a fluid, comprising: areservoir that contains a portion of the fluid; a fluid flow path thatcarries a portion of the fluid; a pressure regulating structure having afirst curve and a second curve defined along the fluid flow path,wherein the pressure regulating structure creates a high-pressure regionalong the fluid flow path and the second curve creates a low-pressureregion along the fluid flow path; wherein the high-pressure regioncauses some of the fluid to exit the fluid flow path through a fluidexit and join the fluid in the reservoir; and wherein the low-pressureregion causes some of the fluid from the reservoir to join the fluidflow path through a fluid entrance.
 19. The pressure regulatingstructure of claim 18, wherein the first curve directs the fluiddownward along the fluid flow path and the second curve directs thefluid upward along the fluid flow path.
 20. The pressure regulatingstructure of claim 18, wherein the first curve and the second curve arearranged in a u-shape configuration.